With the current interest in physical fitness, exercise equipment is enjoying widespread popularity and commercial success. One such type of equipment is the exercise treadmill that, in its simplest form, includes an endless belt that is moved over an underlying track by a walker or runner. Consistent with the advances in electronics, many of these running machines are motor-driven and include microcomputers that control the drive motor, monitor an individual's workout and provide an output display indicating various conditions such as time, speed, and distance.
It is well known that the amount of exertion required to maintain pace with the exercise treadmill can be increased by inclining the running surface so that the runner runs up a grade. Also, inclining the treadmill track can provide the desired level of exertion for patients that are recovering from a cardiac illness and thus use the treadmill as a walking apparatus.
Various mechanisms that raise the front end of the exercise treadmill relative to the floor or other support surface upon which the machine is positioned have been employed to provide an inclined running surface. These mechanisms, however, have not proven to be entirely satisfactory. In particular, because of the weight of the treadmill, such devices are often difficult to operate and adjust properly at the desired height, especially for older persons or those undergoing physical therapy.
The present invention overcomes the disadvantages of these prior developments. In particular, an important aspect of the invention is the provision of a treadmill elevation system in which a gas spring is utilized to provide a substantially "zero-bias" so that the treadmill may be easily raised and lowered to a desired operating position.